JP4344540B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a digital copying machine, a facsimile, or a printer having a function of storing an input image and printing out the stored image.
[0002]
[Prior art]
In an image forming apparatus that forms a multicolor image of a document read by a document reading device or image information sent from a host device, black Bk, cyan C, magenta M, and yellow Y images are formed one by one and superimposed. Therefore, the image forming speed is reduced.
Therefore, while a color image for one screen has been formed on the intermediate transfer member (single chamfering mode), the length is at least twice the reference image size in order to increase the color image forming efficiency. A so-called two-chamfer mode is employed in which a two-screen color image having a reference image size is formed on the intermediate transfer member. Further, in a color image forming apparatus that performs two-chamfering control, control for switching between one-chamfering and two-chamfering is performed.
As an example in which two chamfers are made into one chamfer when an abnormality occurs, for example, Japanese Patent Laid-Open No. 2004-228561 stably stabilizes a high-quality image even when a transfer paper transport time delay occurs and a transfer paper transport time is delayed. The following techniques are shown for the purpose of forming them.
That is, the transfer sheet interval detection unit is a first transfer sheet that secondarily transfers two images formed on the intermediate transfer belt by a transfer sheet detection signal output from a leading end detection sensor provided in the transfer sheet conveyance path. The distance between the trailing edge of the paper and the leading edge of the second transfer sheet is detected. The operation mode changing unit calculates the time interval for the trailing edge of the first transfer paper and the leading edge of the second transfer paper to reach the registration roller from the detected interval of the transfer paper, When the timing is later than the reference timing set by the image interval, the two-chamfering operation mode executed by the central control unit is invalidated, and the operation mode is changed to an operation mode for forming an image for each surface on the intermediate transfer belt. .
Further, for example, in Patent Document 2, an object is to ensure that image formation can be performed over time even if the image interval between two screen images continuously formed on the intermediate transfer belt is reduced. The following technologies are shown as:
That is, in the two-screen formation mode in which a superimposed image is formed on the intermediate transfer belt along the moving direction for two screens, the transfer paper is fed from one of the paper feed trays and the secondary transfer position with the transfer roller. When the time to reach is delayed by a predetermined time or more, when the paper is fed from the paper feed tray from which the transfer paper is sent out, the two-screen formation mode is disabled and only one screen image is formed on the intermediate transfer belt. By providing a control device that performs control to switch to the one-screen forming mode, it is possible to form an image even when transfer paper is delayed due to deterioration of the transport system over time, and the operation of the device is not stopped. .
[0003]
Also, for example, in Patent Document 3, in an image forming system including a one-drum image forming apparatus, printing is started sequentially before all pages are developed regardless of the same or different printing conditions, and as much as possible during printing. The following techniques are shown for the purpose of printing continuously and most efficiently without cycle down.
One-sheet or two-sheet printing based on the determination result of whether or not two-sheet printing can be performed based on printing conditions such as paper size and media, and whether or not two-sheet continuous printing is possible Alternatively, a printing sequence in which two-sheet continuous printing is switched is determined, and the determined printing sequence is controlled to be executed continuously without stopping the rotation of the transfer drum between prints having the same or different printing conditions.
[Patent Document 1]
JP 2000-039813 A
[Patent Document 2]
JP 2000-137422 A
[Patent Document 3]
JP 2000-255134 A
[0004]
[Problems to be solved by the invention]
In the prior art, switching from the two-chamfer control to the one-chamfer control is mainly based on the condition on the engine side.
However, in an actual color machine, it is necessary to determine whether or not to perform two-sided chamfering from the viewpoint of whether or not an image can be prepared, as well as the two-sided chamfering condition for reasons of the engine. If this is not taken into consideration, the image preparation is delayed and in the worst case, an image shift occurs between the colors and miscopying occurs.
Here, in the case where the two-sided image cannot be obtained because the preparation of the image formation image is not in time, it can be predicted from the mode factors to some extent in advance, but the resource state of the HDD for image formation changes every moment. It is difficult to accurately predict image preparation.
Therefore, the present invention provides an image forming apparatus having a recovery mode in which image misalignment is output and output is normally performed without outputting miscopy even when a situation occurs in which image preparation is not in time during two-sided image capture. The purpose is to provide.
Specifically, it is an object of the present invention to define basic configuration means for preventing miscopying of an abnormal image or the like even when the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence.
It is an object of the present invention to define a standard for making the control content of the two-chamfer recovery control means different.
It is an object of the present invention to enable satisfactory two-chamfering mode printing that does not cause an image abnormality by the recovery process even when the first image preparation of the two-chamfering sequence is not in time.
According to a fifth aspect of the present invention, even when the second image preparation of the two-sided chamfering sequence is not in time, it is possible to perform good two-sided chamfering mode printing without causing an image abnormality by the recovery process.
The object of the present invention is to specify a recovery method.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a superimposed color image is formed for two screens along the moving direction of the intermediate transfer member, and the superimposed images for the two screens are continuously transferred onto the transfer paper. In a color image forming apparatus having a two-chamfering mode for transferring toAn image preparation unit that prepares information on the color image to be formed on a storage device for each color component, and the image preparation unit continuously forms a superimposed image for the two screens.Image preparation availability determination means for determining whether or not an image can be prepared at the two-chamfer sequence timing, first two-chamfer sequence control means for performing the two-chamfer sequence, and the first or second in the two-chamfer sequence A second two-chamfering sequence control means for suppressing the second image formation, a third two-chamfering sequence control means for suppressing both the first and second image formation in the two-chamfering sequence, and the image preparation If it is determined by the availability determination means that the image is not in time, one of the first two chamfering sequence control means, the second two chamfering sequence control means, and the third two chamfering sequence control means is selected and operated. A central control unit having a function as a two-chamfer recovery control means for controllingWhen the image preparation availability determination unit determines that the preparation of the first image in the two-chamfering sequence is not in time, the second chamfering recovery control unit selects the second two-chamfering sequence control unit and selects the second chamfering sequence control unit. The second two-chamfering sequence control is performed by suppressing the image formation of the first image that has not been ready and operated after suppressing the image formation of the second image that has been prepared in time. After selecting and operating the means, the first two-chamfering sequence control means is selected and operated, and the image preparation availability determination means is in time for the image preparation relating to the second image formation in the two-chamfering sequence. If it is determined that the second two-chamfering sequence control means is selected, the second image which is not in time for the preparation is suppressed and the operation is performed. Wherein said that the preparation is to work by suppressing image formation of the first image in time after.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus includes a scanner unit 1, a printer unit 2, and a paper feed unit 3. The scanner unit 1 sends image information of a document placed on a contact glass 11 to a color CCD 13 by an optical scanning unit 12 having a light source, a plurality of mirrors and lenses, and turns the red R, green G, and blue B by the color CCD 13. Color separation is performed and each color is read and converted into an electrical image signal. The image signal color-separated into R, G, and B is subjected to color conversion processing by the image processing unit, converted into color image data of black Bk, cyan C, magenta M, and yellow Y, and sent to the printer unit 2.
The printer unit 2 includes an image forming unit 21, a fixing unit 22, and a transfer paper transport unit 23. As shown in the configuration diagram of FIG. 2, the image forming unit 21 includes a photoreceptor 24, a revolver unit 25, a transfer unit 26, and a writing unit 27. A neutralizing lamp 28, a charging charger 29, a revolver unit 25, a toner adhesion amount sensor 30, a pre-transfer neutralizing lamp 31, a transfer unit 26, and a drum cleaning unit 32 are provided along the rotation direction of the photosensitive member 24.
The revolver unit 25 includes developing devices 251, 252, 253, and 254 for black Bk, cyan C, magenta M, and yellow Y, and a revolver home position sensor 255. The transfer unit 26 is wound around a plurality of rollers, an intermediate transfer belt 261 having a reference mark 262, a belt transfer charger 263, a mark sensor 264 for reading the reference mark 262, a paper transfer charger 265, and the like. A belt cleaning portion 266 is provided.
The intermediate transfer belt 261 has, for example, two sheets of A4 horizontal size, transfer paper, and a length twice the circumference of the photoconductor 24 including the interval, and the intermediate transfer belt 261 is rotated by two rotations of the photoconductor 24. 2 images can be formed with the same color. The transfer paper transport unit 23 provided on the upstream side of the paper transfer charger 265 is disposed upstream of the registration roller 231 for feeding the transfer paper and a predetermined distance Lr from the registration roller 231 to detect the leading edge of the transfer paper. It has a tip detection sensor S1.
The paper feed unit 3 has a plurality of paper feed trays 41, 42, and 43. Each of the paper feed trays 41 to 43 has a paper feed claw 44 and a paper feed roller 45. Transfer paper detection sensors S2, S3, and S4 for detecting the transfer paper are provided. The transfer paper fed from the paper feed unit 3 is sent to the transfer paper transport unit 23 by a transport roller 46 provided at the outlet of the paper feed unit 3.
[0007]
As shown in the block diagram of FIG. 3, the control unit 5 of the image forming apparatus controls the operations of the scanner unit 1, the printer unit 2, and the paper feed unit 3, and displays the operation state on the display unit 4. A control unit 51, a transfer sheet interval detection unit 52, and an operation mode change unit 53 are provided.
The transfer sheet interval detection unit 52 inputs transfer sheet detection signals from the leading edge detection sensor S 1 provided in the printer unit 2 and the transfer sheet detection sensors S 2, S 3, S 4 provided in the sheet feeding unit 3 to the intermediate transfer belt 261. When performing two-sided chamfering to form an image for two sides, the interval between the trailing edge of the first transfer sheet sent and the leading edge of the transfer sheet sent to the second sheet is detected.
The operation mode changing unit 53 disables the two-sided operation mode when the interval between the first transfer sheet and the second transfer sheet detected by the transfer sheet interval detection unit 52 is delayed from a predetermined reference value. Thus, the operation mode is changed to the operation mode in which the image is formed on each surface on the intermediate transfer belt 261.
When the image forming apparatus configured as described above forms one full color image, the image forming unit 21 rotates the intermediate transfer belt 261 of the photosensitive member 24 and the transfer unit 26, and the mark sensor of the transfer unit 26. In 264, reading of the black Bk image data is started at a predetermined timing after the reference mark 262 of the intermediate transfer belt 261 is detected. Based on the black Bk image data, the optical writing unit 27 applies electrostatic latent image to the photosensitive member 24. Form an image.
The electrostatic latent image formed on the photoreceptor 24 is visualized by the black Bk developing unit 251 of the revolver unit 25. The visualized black image Bk is primarily transferred to the intermediate transfer belt 261 by the belt transfer charger 263 at a timing based on the detection of the reference mark 262 of the intermediate transfer belt 261 by the mark sensor 264. When the primary transfer of the black image Bk of the first color is completed, the revolver unit 25 is rotated to bring the cyan C developing device 252 into contact with the photosensitive member 24.
Thereafter, a cyan image C is formed on the photosensitive member 24 in the same manner as described above, and the formed cyan image C is primarily transferred to the intermediate transfer belt 261 at a timing based on the detection of the reference mark 262 by the mark sensor 264. The first color black image Bk and the second color cyan image C are superimposed. This image formation and primary transfer are repeated for each image of magenta M and yellow Y, and a full color toner image is formed on the intermediate transfer belt 261.
[0008]
The full-color toner image formed on the intermediate transfer belt 261 is secondarily transferred to the transfer paper sent from the transfer paper transport unit 23 by the paper transfer charger 265, and the transfer paper onto which the full-color toner image has been transferred is the transfer paper transport belt. 33 is sent to the fixing unit 22 where it is fixed and discharged. A belt cleaning unit 266 is brought into contact with the intermediate transfer belt 261 on which the toner image is secondarily transferred to the transfer paper, and the toner remaining on the surface of the intermediate transfer belt 261 is removed to prepare for the next image formation. .
When forming an image of one color, it is not necessary to superimpose toner images of different colors on the intermediate transfer belt 261. Therefore, image formation is started without particularly detecting the reference mark 262, and writing is performed at a predetermined timing. Development, primary transfer, secondary transfer, and cleaning of the intermediate transfer belt 261 are sequentially performed. Further, when a plurality of images are continuously formed, image formation is performed at a necessary image interval regardless of the rotation of the intermediate transfer belt 261.
In the two-chamfering operation mode in which a full-color image is formed on the intermediate transfer belt 261 by two sides, when the intermediate transfer belt 261 rotates and the mark sensor 264 detects the reference mark 262, the first black image Bk1 is displayed. As shown in the development view of FIG. 4, the black image Bk1 formed on the photoconductor 24 is transferred to the belt transfer charger 263 at a timing based on the detection of the reference mark 262 of the intermediate transfer belt 261 by the mark sensor 264. Thus, primary transfer is performed on the intermediate transfer belt 261. Subsequently, a second black image Bk2 is formed on the photosensitive member 24, and the formed black image Bk2 is primarily transferred to an area after the area where the black image Bk1 is transferred on the intermediate transfer belt 261.
When the secondary transfer of the black images Bk1 and Bk2 of the first color is completed, the revolver unit 25 is rotated so that the cyan C developing device 252 is brought into contact with the photosensitive member 24, and the first cyan is applied to the photosensitive member 24 in the same manner as above. An image C1 is formed, and the formed cyan image C1 is primarily transferred to the intermediate transfer belt 261 at a timing based on the detection of the reference mark 262 by the mark sensor 264, and the first color black image Bk1 and the second color cyan image. Overlay C1. Thereafter, a second cyan image C2 is formed on the photosensitive member 24, and the formed cyan image C2 is primarily transferred onto the intermediate transfer belt 261 and superimposed on the black image Bk2.
[0009]
This image formation and primary transfer are repeated for each of the magenta M and yellow Y images, and the first full color image FC1 and the second full color image FC2 are formed on the intermediate transfer belt 261. After starting the image formation of the yellow Y image, which is the final color of the first image FC1, the registration roller 231 is rotated at a constant secondary transfer timing, and the first full color image FC1 is transferred onto the transfer paper. The second full color image FC2 is secondarily transferred to the transfer paper and fixed on the transfer paper that is subsequently transferred and fixed.
When the two images FC1 and FC2 are formed on the intermediate transfer belt 261 in this way, as shown in FIG. 4, if the circumferential length of the intermediate transfer belt 261 is L, the leading edge and the second face of the first image FC1 are displayed. When the distance La of the leading edge of the image FC2 is made constant regardless of the image length, that is, the length of the transfer paper for secondary transfer, various image formation control timings can be simplified regardless of the transfer paper size. The distance LD1 between the image FC1 on the first side and the image FC2 on the second side, that is, the interval between the two transfer papers sent in the case of two-sided chamfering is the maximum transfer paper length for performing two-sided chamfering, for example, the length of A4 size or LT Minimum when the size is short.
The interval LD1 is determined to be an operable length according to the transfer paper feed interval, the return speed of the scanner unit 1, and the like. Further, the distance LD2 from the end of the image FD2 on the second surface to the start end having the reference mark 262 of the intermediate transfer belt 261 is a portion that does not affect the sheet spacing of the transfer paper. The color change speed of the revolver unit 25 and the scanner unit 1 The return speed is determined, and LD1 = LD2 is normally set.
[0010]
FIG. 5 is a block diagram showing an internal configuration of the image processing unit (IPU) 100. The document image information from the optical scanning unit 12 is photoelectrically converted by the color CCD 13 and converted into a digital signal by the A / D converter 61. The image signal converted into the digital signal is subjected to shading correction by the shading correction unit 62 and then subjected to MTF correction, γ correction, and the like by the image processing unit 63. The image signal that has passed through the scaling unit 72 is enlarged / reduced in accordance with the scaling factor and flows to the selector 64.
The selector 64 switches the destination of the image signal to either the writing γ correction unit 71 or the image memory controller 65. The image signal that has passed through the writing γ correction unit 71 is corrected for writing γ in accordance with the image forming conditions, and is sent to the writing unit 57. Between the image memory controller 65 and the selector 64, an image signal can be input and output bidirectionally.
Although not explicitly shown in FIG. 5, the image processing unit (IPU) includes image data supplied from the outside (for example, from a data processing device such as a personal computer) in addition to the image data input from the scanner unit 1. (Output data) has a function of inputting / outputting a plurality of data.
Further, a CPU 68 for setting the image memory controller 65 and the like and controlling the scanner unit 1 and the writing unit 57, and a ROM 69 and a RAM 70 for storing programs and data thereof are provided. Further, the CPU 68 can write and read data in the image memory 66 via the image memory controller 65.
[0011]
Next, details of the image memory controller 65 and the image memory 66 in FIG. 5 will be described with reference to FIG. FIG. 6 is a diagram showing details of individual storage devices of the storage means in the present invention, and shows that the image memory 66 is also connected to the individual storage devices.
The data input / output control unit includes blocks of an input data selector 201, an image composition unit 202, a primary compression / decompression unit 203, an output data selector 204, and a secondary compression / decompression unit 205. Setting of control data in each block is performed by the CPU 68. The addresses and data shown in FIG. 5 correspond to the image data, and the data and addresses connected to the CPU 68 are not shown.
The image memory 66 includes primary and secondary storage devices 206 and 207. The primary storage device 206 is substantially synchronized with the data transfer speed required for inputting / outputting image data when writing data to the specified area of the memory or reading data from the specified area of the memory at the time of image output. For example, a memory capable of high-speed access such as DRAM is used. Further, the primary storage device 206 has a configuration (interface unit with the image memory controller 65) that can be divided into a plurality of areas according to the size of the image data to be processed and can simultaneously input and output image data. .
[0012]
The secondary storage device 207 is a large-capacity nonvolatile memory for synthesizing and sorting input images and for accumulating data. If the primary storage device 206 has a sufficient capacity for processing image data and is non-volatile, it is not necessary to input / output data to / from the secondary storage device 207. If the secondary storage device 207 can write / read data substantially in synchronization with the data transfer speed required at the time of image input / output, the data can be directly written / read to / from the secondary storage device 207. It becomes possible. In such a case, it is possible to process data without distinguishing between primary and secondary.
When the secondary storage device 207 cannot write / read data in synchronization with the data transfer speed required at the time of image input / output, for example, a storage medium such as a hard disk or a magneto-optical disk is used for the secondary storage device 207 Even in such a case, the primary storage device 206 is interposed when data is input / output to / from the secondary storage device 207, so that processing according to the data transfer capability of the secondary storage device 207 is possible.
[0013]
Here, a specific usage example of the primary storage device 206 and the secondary storage device 207 in each application will be given.
<Example 1> One copy in a copy application
In the case of one copy, first, image data from the scanner unit 1 is input to the primary storage device 206. The data is output to the printer unit 2 at almost the same timing, but at the same time, the data is stored in the secondary storage device 207. When the image formation is completed normally, the data stored in the secondary storage device 207 is erased without being used. However, when a jam occurs, the jam is obtained by reading the image data from the secondary storage device 207. There is no need to read an image from the scanner unit 1 after the occurrence.
<Example 2> Sorting in a copy application (multiple copies)
Even in the case of two or more copies, image data from the scanner unit 1 is first input to the primary storage device 206. The first copy is output from the primary storage device 206 to the printer unit 2 and the data is also saved in the secondary storage device 207 at the same time, as in <Example 1> above. The second and subsequent image data are output to the secondary storage device 207 → the primary storage device 206 → the printer unit 2, so that the scanner unit 1 does not need to read the second and subsequent copies. When the required number of copies is completed, the image data stored in the secondary storage device 207 is deleted.
<Example 3> Image accumulation from the scanner unit 1
In this case, the image data from the scanner unit 1 is stored in the secondary storage device 207 via the primary storage device 206. In this case, the image data remains stored unless intentional deletion is performed.
<Example 4> Printing from an external input device (for example, a personal computer)
In this case, it is almost the same as <Example 1> and <Example 2>, and the input source of the image data is not the scanner unit 1 but the external input device.
<Example 5> Image storage from an external input device
In this case, it is almost the same as <Example 3>, and the input source of the image data is not the scanner unit 1 but the external input device.
<Example 6> Printing accumulated image
When the images accumulated in <Example 3> and <Example 5> are printed, they are printed by the secondary storage device 207 → the primary storage device 206 → the printer unit 2.
[0014]
Next, an operation example of the image memory controller 65 will be described. Here, an example in which the secondary storage device 207 cannot write / read data substantially in synchronization with the data transfer speed required at the time of image input / output is shown.
<1> Image input (save to image memory 66)
The input data selector 201 selects image data to be written to the image memory (primary storage device 206) from a plurality of data. The image selected by the input data selector 201 is supplied to the image composition unit 202 and is synthesized as necessary.
The image data processed by the image composition unit 202 is compressed by the primary compression / decompression unit 203, and the compressed data is written to the primary storage device 206. The data written in the primary storage device 206 is further compressed by the secondary compression / decompression unit 205 as necessary, and then stored in the secondary storage device 207.
<2> Image output (reading from image memory 66)
When outputting an image, the image data stored in the primary storage device 206 is read. When the image to be output is stored in the primary storage device 206, the primary compression / decompression 203 decompresses the image data in the primary storage device 206, and the decompressed data or the decompressed data The data after the image composition of the input data is selected by the output data selector 204 and output.
When the image to be output is stored in the secondary storage device 207, the output target image data stored in the secondary storage device 207 is expanded by the secondary compression / decompression unit 205, and the decompressed data Is written in the primary storage device 206, and then the above-described image output operation is performed.
[0015]
Next, image input / output control using the page memory will be described. The page memory is configured in the primary storage device 206, and temporarily holds images in units of pages.
Although the size of the normal page memory changes according to the resolution or the like, the memory capacity of the A4 size unit is managed as one page unit. For example, when there is an A3 size input, image input is performed using two pages of page memory. In the case of color input, image data of M (magenta), C (cyan), Y (yellow), and K (black), which are color components of the color, is input from the scanner unit 1 to the page memory for each color component.
The same applies to output. If there is a color component to be printed on the page memory, the image data developed on the page memory is output to the printer unit 2. When the color component of the designated image does not exist on the page memory and exists in the secondary storage device 207, first, the designated image is read from the secondary storage device 207 to the page memory, and then the image data is transferred to the printer unit 2. Output.
In the case of a color copying machine, there is a function called an ACS (Auto Color Select) mode that automatically determines the color of an image of an original image and performs copying in either monochrome or full color.
[0016]
The operation of the image forming apparatus of the present invention will be described below. First, FIGS. 7 and 8 show a single chamfering sequence and a two chamfering sequence. In the single chamfering sequence, one image is formed in the order of K, C, M, and Y. With this as one cycle, full-color printing is performed by repeating a single chamfering sequence.
On the other hand, in the two-chamfering sequence, image formation for two images is performed for each color component, and image formation is performed in the order of M, K, C, M, and Y. In the case of two chamfers, when the same image size is used compared to single chamfering, the image forming interval is about half as short, so the time to prepare the images is short. End up.
Whether or not the two-chamfering is in time is whether the paper size, the paper size direction, two image forming requests are aligned by the two-chamfering timing, are two or more images formed, or are the colors used in the two surfaces the same? The image preparation was realized by a hardware configuration and a productivity setting with sufficient time.
However, in recent years, color copiers have become more multifunctional and image finishing in complicated modes is required. Furthermore, multi-applications such as FAX, printer copy, and scanner are used, and there are problems such as resource contention. Furthermore, there is a demand for higher printing speed, and there are various factors that tend to cause delay in image preparation. For this reason, it has become necessary to determine whether or not two-chamfering control is possible from the viewpoints of both image forming conditions and whether or not image preparation is possible.
[0017]
9 is a diagram showing a first recovery example when image preparation is not in time in P1-C of FIG. 8, FIG. 10 is a diagram showing a second recovery example, and FIG. 11 is an image of P2-C in FIG. FIG. 12 is a diagram showing a recovery example when preparation is not in time, FIG. 12 is a diagram showing a first control example, FIG. 13 is a diagram showing a second control example, FIG. 14 is a diagram showing a third control example, and FIG. These are figures which show the 4th control example.
First, FIG. 12 shows a schematic flow in the case where image preparation is not in time during execution of two chamfering. If the image preparation is not in time during execution of the two chamfering in S11 and S12 (image preparation availability determination means), the normal two chamfering control is temporarily canceled in S15 (first two chamfering sequence control means). In S16, it is determined whether the first or second image preparation of the two-chamfering sequence control is not in time, and the recovery control is performed in S17 and S18 (two-chamfering recovery control means) in the first and second, respectively. It is different.
Details of S17 and S18 are shown in the flowcharts of FIGS. 13 and 14, respectively. FIGS. 13 and 14 are examples in the case where the first image preparation of the two-chamfering sequence control is not in time, and two types of recovery examples are shown. Examples of operations of FIGS. 13 and 14 are shown in FIGS. 9 and 10, respectively.
In FIG. 13 (FIG. 9), since P1-C is not in time in (2) of FIG. 9, image formation of this image is suppressed (S30). At the same time, even if image preparation is in time, P2-C also suppresses image formation. (Third two chamfering sequence control means). Then, as a recovery process, image formation of the corresponding color component is performed again in (3). Since image formation is suppressed in (2) for both P1-C and P2-C, after (3), the normal two-sided image formation sequence may be continuously executed from the color components whose image preparation is not in time.
FIG. 14 (FIG. 10) shows an example in which image formation of this image is suppressed because P1-C is not in time in (2) of FIG. 9 (S40), and at the same time, image preparation is in time, so image formation of P2-C is executed. (S41) (second two-chamfering sequence control means). Then, as a recovery process, image formation of the corresponding color component is performed again in (3). Since the image formation of P1-C is suppressed by (2) and the image formation of P2-C is performed, only the image formation process of P1-C is executed in (3). After (4), the normal two-sided imaging sequence is continuously executed.
FIG. 15 is an example of recovery when the first or second image preparation of the two-chamfer sequence control is not in time. FIG. 11 shows an operation example of the flow of FIG.
In FIG. 15 (FIG. 11), since P2-C is not in time in (2) of FIG. 11, image formation of this image is suppressed (S50), and image formation of the corresponding color component is performed again in (3). Since P1-C has already been imaged in (2), image formation is not performed and only P2-C is imaged. After (4), the normal two-sided imaging sequence is continuously executed.
By executing the recovery mode as described above, normal output can be performed without outputting a miscopy due to image misalignment even when a situation occurs in which image preparation is not in time during the two-sided scanning.
[0018]
【The invention's effect】
As described above, according to the first aspect, the basic configuration means for detecting a state in which the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence and preventing a miscopy of an abnormal image or the like is defined. As a result, even if a state in which the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence occurs, good image formation without miscopying becomes possible.
According to the second aspect of the present invention, it is possible to accurately perform the recovery control in the two-chamfering mode by defining the reference for changing the control contents of the two-chamfering recovery control means.
According to the third aspect, even when the first image preparation of the two-sided chamfering sequence is not in time, it is possible to perform good two-sided chamfering mode printing without causing an image abnormality by the recovery process.
According to the fourth aspect, even when the first image preparation of the two-sided chamfering sequence is not in time, it is possible to perform good two-sided chamfering mode printing without causing an image abnormality by the recovery process.
According to the fifth aspect, even when the second image preparation in the two-sided chamfering sequence is not in time, it is possible to perform good two-sided chamfering mode printing without causing an image abnormality by the recovery process.
According to the sixth aspect of the present invention, by detecting a state incapable of executing the two-chamfering sequence during execution of the two-chamfering sequence and defining a basic configuration means for preventing miscopying of an abnormal image or the like, Even if a state in which the two-sided chamfering sequence cannot be executed during execution of the sequence occurs, good image formation without miscopying becomes possible.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of an image forming unit.
FIG. 3 is a block diagram of a control unit.
FIG. 4 is a development view of an intermediate transfer belt.
FIG. 5 is a block diagram of an image processing unit (IPU).
FIG. 6 is a block diagram of an image memory controller and an image memory.
FIG. 7 is a diagram showing a single chamfering sequence.
FIG. 8 is a diagram showing a two-chamfering sequence.
FIG. 9 is a diagram illustrating a first recovery example when image preparation is not in time for P1-C in FIG. 8;
FIG. 10 is also a diagram illustrating a second recovery example.
FIG. 11 is a diagram illustrating a recovery example when image preparation is not in time in P2-C of FIG.
FIG. 12 is a diagram illustrating a first control example.
FIG. 13 is a diagram illustrating a second control example.
FIG. 14 is a diagram illustrating a third control example.
FIG. 15 is a diagram illustrating a fourth control example.
[Explanation of symbols]
51 Central control unit, 261 Intermediate transfer belt

Claims (1)

In a color image forming apparatus having a two-chamfering mode in which a superimposed color image is formed for two screens along the moving direction of the intermediate transfer member, and the superimposed images for the two screens are continuously transferred to transfer paper . The image preparation means for preparing the information of the color image to be stored on the storage device for each color component, and the image at the two chamfering sequence timing in which the image preparation means continuously forms the superimposed images for the two screens. Image preparation availability determination means for judging whether or not image preparation is possible, first two-chamfering sequence control means for performing a two-chamfering sequence, and suppressing the first or second image formation in the two-chamfering sequence A second two-chamfering sequence control means, a third two-chamfering sequence control means for suppressing both first and second image formation in the two-chamfering sequence, If it is determined by the image preparation availability determination means that the image is not in time, one of the first two-chamfering sequence control means, the second two-chamfering sequence control means, and the third two-chamfering sequence control means is selected. a central control unit having a function as 2 chamfer recovery control means for controlling to operate Te,
The two-chamfer recovery control means
When the image preparation availability determination unit determines that the preparation of the first image in the two-chamfering sequence is not in time, the second two-chamfering sequence control unit is selected to prevent the first preparation from being in time. After suppressing the image formation and operating the second image in preparation, or after selecting and operating the third two-chamfer sequence control means Selecting and operating the first two chamfering sequence control means;
When the image preparation availability determination unit determines that the preparation of the image related to the second image formation in the two-chamfering sequence is not in time, the second two-chamfering sequence control unit is selected and the preparation is not in time. An image forming apparatus comprising: operating after suppressing the image formation of the second image and suppressing the image formation of the first image in time for the preparation .

Images